During the processing of a substrate in the plasma processing chamber, satisfactory results often require tight control of the process parameters. This is particularly true for processes such as deposition, etching, cleaning, etc., that are employed to manufacture modern high density integrated circuits. When the processing parameters (such as bias voltage, RF power, ion flux, plasma density, pressure, etc.) exceed a narrow, pre-defined window, a process excursion is said to have occurred. These process excursions represent undesirable events that often lead to undesirable processing results (e.g., poor etch profile, low selectivity, etc.). Accordingly, the detection, characterization, and avoidance of process excursions are important tasks for process engineers in the manufacture of integrated circuits.
Detecting process excursions is often performed via monitoring of various process parameters. Some process parameters (such as bias voltage, reflected power, etc.) may be measured directly while others may be inferred from measured parameters.
In-situ arcing is a type of process excursion that has the potential to decrease yield, damage the substrate and/or damage the chamber components. Arcing can occur between features on a substrate, between the substrate and its surrounding components such as the grounded chamber components, and between chamber components, for example. There can be many causes for arcing. Irrespective, arcing represents an uncontrolled event that is almost always undesirable and/or has the potential to create undesirable damage and/or undesirable process results.
Accordingly, the detection of in-situ arcing is important for the purpose of diagnostic and recipe adjustment in order to improve process results and process yield, as well as to avoid damage to the substrate and/or the chamber components.